The popular Highlanders and Otago player recently had surgery to fix a heart valve.

The problem was detected in early January and cut his 2014 season to just one appearance, against the Crusaders in a preseason match.

Highlanders team doctor Greg Macleod said today: "Due to the nature of the surgery and what the surgeons were required to do to alleviate any ongoing issues, Buxton has been advised to stop playing rugby."

Popoalii, who had surgery in Auckland last week, has been discharged from hospital and is recuperating well.

Highlanders chief executive Roger Clark said: "This is obviously a tough time for Buxton and his family. While we are delighted the operation has gone well and the outlook for his health is positive, we are naturally feeling for him and respect and fully support his decision to retire from rugby.

"I know the team and management have great admiration for Bucky and wish him a speedy recovery from his operation."

Popoalii played 15 games for the Highlanders, making his debut against the Chiefs in 2012, and was known as a winger with a big sidestep and blistering pace off the mark.